样例全过了, 但不知道代码哪里错了WA #3 ~ #10

求调!!!

code(20pts, cpp):

#include <bits/stdc++.h>
using namespace std;
const int N = 55, M = 6000;
typedef pair<int, int> PI;
typedef pair<int, PI> PII;
struct node
{
    int to, next, len;
} a[M];
int pre1[N], pre2[N], idx, r[N];
int d[N];
bool f[N];
int cnt[N], vis[10000];
int n, m, s, t, k, tmp;
void print()
{
    for (int i = 1; i < tmp; i++)
        cout << r[i] << '-';
    cout << r[tmp];
}
void add(int pre[], int u, int v, int len)
{
    a[++idx] = {v, pre[u], len};
    pre[u] = idx;
}
void dijkstra()
{
    priority_queue<PI, vector<PI>, greater<PI>> heap;
    memset(d, 0x3f, sizeof(d));
    heap.push({0, t});
    while (!heap.empty())
    {
        PI h = heap.top();
        heap.pop();
        int p = h.second, dis = h.first;
        if (f[p])
            continue;
        f[p] = true;
        for (int i = pre2[p]; i != 0; i = a[i].next)
        {
            int to = a[i].to;
            if (dis + a[i].len < d[to])
            {
                d[to] = dis + a[i].len;
                heap.push({dis + a[i].len, to});
            }
        }
    }
}
void astar()
{
    priority_queue<PII, vector<PII>, greater<PII>> heap;
    heap.push({d[s], {0, s}});
    while (!heap.empty())
    {
        PII h = heap.top();
        heap.pop();
        int p = h.second.second, dis = h.second.first;
        cnt[p]++;
        if (!vis[p])
        {
            r[++tmp] = p;
            vis[p] = 1;
        }
        if (cnt[t] == k)
        {
            print();
            return;
        }
        for (int i = pre1[p]; i != 0; i = a[i].next)
        {
            int to = a[i].to;
            if (cnt[to] < k)
                heap.push({dis + a[i].len + d[to], {dis + a[i].len, to}});
        }
    }
    cout << "No";
}
int main()
{
    scanf("%d%d%d%d%d", &n, &m, &k, &s, &t);
    int x, y, len;
    while (m--)
    {
        scanf("%d%d%d", &x, &y, &len);
        add(pre1, x, y, len);
        add(pre2, y, x, len);
    }
    dijkstra();
    astar();
    return 0;
}